Boiler tail smoke duct with built-in denitration smoke bypass

Abstract

The invention discloses a boiler tail smoke duct with a built-in denitration smoke bypass, and belongs to the field of boiler denitration. A plurality of heated faces are arranged in the boiler tail smoke duct, at least one smoke bypass smoke duct with the width being boiler tail smoke duct full width or partial width is further arranged in the boiler tail smoke duct, the smoke bypass smoke ducts are connected with one or more stages of heated faces in parallel, and outlets of the smoke bypass smoke ducts are combined into an outlet of the boiler tail smoke duct. According to the boiler tail smoke duct, the built-in denitration smoke bypass smoke ducts integrated with the boiler tail smoke duct are adopted, the investment cost is saved, the boiler floor space is reduced, and the denitration inlet smoke temperature is more even.

Description

technical field [0001] The invention belongs to the field of boiler denitrification, and in particular relates to a tail flue of a boiler SCR denitrification system. Background technique [0002] Large-scale power plant boilers often participate in peak regulation, and the flue gas temperature at the inlet of the SCR denitrification device will be lower than the full load during low-load operation. When the flue gas temperature is too low to meet the denitrification operation conditions, the flue gas bypass flue can be set to reduce the heat exchange between the heating surface and the flue gas in the tail flue of the boiler, and increase the flue gas temperature at the denitrification inlet to meet the denitrification operation conditions. [0003] The existing flue gas bypass flue schemes are all external, such as figure 1 Shown: A heating surface is arranged in the tail flue of the boiler, the denitrification device is arranged after the tail flue of the boiler, and the ...

AI Technical Summary

Problems solved by technology

[0005] 1) Limited by the external structure, the circulation area of ​​the bypass itself is relatively small. At the same time, it is limited by the opening of the cladding wall and the bypass flue must pass through the boiler steel structure guide layer frame beams and trusses, so it cannot be designed too wide, so a certain amount of space is required. Depth, therefore, for new units, the depth of the bypass flue may affect the boiler column spacing, resulting in increased boiler footprint

[0006] 2) The position where the flue gas from the denitrification bypass flue is introduced into the main flue is close to the ammonia injection device and the catalyst. Since the bypass flue is not full-width, it cannot ensure that the flue gas is mixed evenly along the entire width of the boiler, which may cause catalyst Uneven inlet smoke temperature

During operation, there may be ammonium bisulfate deposition in local low smoke temperature areas, which will affect the safe and economical operation of the boiler

Images